Internal-combustion engine



13 1926. 1,580,420- Apnl w. l.. DEMPSEY INTERNAL GOMBUSTNN ENGINE Filed Sept.y 21, 1921 ps e jfl/nf ATYys.

Patented Apr. 13, 192.6.

UNITED STATES PATENT ol-F1cE.--v

WILLIAM L. DEMPSEY, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T0 DEMPBEY CYCLE COMPANY INCORPORATED, 0F PHILADELPHIA, PENNSYLVANIA, A COB- PORATION OF DELAWARE.

INTEBNAL-COMBUSTION ENGINE.

-Applioation led September 21, 1921. Serial No. 502,242.

To all whom z't may concern.' c

Be it known that I, WILLIAM L. DEMPsEY, a citizen of the United States, and resident of Philadelphia, county of Philadelphia, State of Pennsylvania, have invented an Imrovement in Internal-Combustion Engines, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts.

This invention relates to improvements in internal combustion engines1 and the general object of the invention is to provide means for improving the eiciency and econom of an internal combustion engine in which an explosive mixture of hydro-carbon and air 1s introduced into the combustion chamber of the engine and ignited therein.

Internal combustion engines, such as are employed as motors for automobiles, tractors, aeroplanes, etc., are very inconstant because of the multifarious demands suddenly made-upon them. The speed must vary in a short time from zero to two or three thousand revolutions per minute and when runnin at a high rate of speed the chambers wit in their c linders vary from three thousand degrees ahrenheit to a temperature so low that a highly combustible gas requires` a spark to ignite it after compression has raised the minimum temperature three or four hundred degrees Fahrenheit. The load on lthe piston is suddenly shifted from zero to full capacity, and the ressures within the cylinders vary from be ow atmospheric pressure to from two to five hundred pounds per square inch. Compression pressures, explosives pressures, and exhaust pressures vary widely every moment. In an almost inappreciable extent of time the combustion chamber' must receive and utilize fuels, which, while fairly constant rin chemical analysis, vary in molecular structure, in different degrees of vaporization, in temperatures, and in mixtures from lean to rich.

The present invention contemplates the stabilization or making the operation of an internal combustion engine more constant and uniform.

The present application is a continuation in part of m prior application No. 262,669, filed Novem r 15, 1918, Patent Number 1,496,453 granted June 3, 1924 and comprises certain improvements in the invention` disclosed in that application.

The present improvement uponthe invention aforesaid relates more particularly to providing means for reducing the rapid change in temperature of the explosive mixture during its passage from the carbureter or' heated manifold into the combustion chamber of the cylinder and to prevent condensation Within the cylinder and also in providing means for more thoroughly disintegrating and mixing the globules of fuel with the air by which it is entrained.

A further object of the invention is to provide means for maintaining a more uniform temperature of the mixture under low and medium throttle conditions, as wet` mixtures in the cylinder and manifold occur at l relatively low throttles because there is less heat, greater vacuum and a greater length of time for heat transference than when the .engine is running under full load with open throttle.

More specifically the' present invention contemplates the supplying of heat necessary to vaporize the fuel charge as closely as may be to its entrance into the combustion .chamber ofthe cylinder, both in point of time and position, for the temperature changes Within the combustion chamber takeplace with sufficient velocity to permit the admission of one thousand or more charges per minute into a c linder without pre-ignition, immediately a ter the temperature has risen, at the time of the explosion; to twent tive hundred or three thousand degrees ahrenheit. The almost instantaneous complete vaporization of the charge of fuel and thorough mixture with thev entraining air in the u per portion of the cylinder, irrespective o the s' eed of the en' ine, or osition of the t rottle, is, there ore, very 1m ortant. This heating and disintegration of t e fuel is accom lished in the present invention by projectmg a thin film of the explosive mixture of hydro-carbon and air upon the highly heated surface, preferabl the wall of the inlet aperture ofthe cylin er, and causing the A further feature of the invention consists in providing a by-pass in the portion of the cylinder through which the charge 1s admitted and providing means for igniting the explosive mixture passing through said bypass thus insuring the ignition of the fuel.

Other objects and features of the invention will more fully appear from the following description and the annexed drawings and will be pointed out in the claims.

A preferred construction embodying the invention is illustrated ir the accompanying drawings, in which,

Fig. l is a vertical longitudinal sectional View of a cylinder and piston provided with an induction system for the fue] en'ihodying my invent ion;

Fig. 2 is ahorizontal sectional view throu h the valve casing, on line 2 2, Fig. 1; an

Fig. 3 is an enlarged detail sectional view showing the valve open to admit the charge of explosive mixture, and indicating in dotted lines the manner in which the globules of fuel are caused to strike against the highly heated wall of the inlet aperture in the cylinder in such a manner as to break up the globules and deflect the same in converging lines so that such globules of fuel as enter the cylinder will impingc upon other globules and be broken upand thoroughly mixed with the entraining air.

A single cylinder embodying the invention is shown in the accompanying drawing, but it Will be understood that the same is illustrative of the system as applied to a. plurality of cylinders, such as are commonly used in motors for automobiles and other devices. It will also be understood that the piston which is reciprocable in the cylinder is employed to operate the usual crank shaft and other mechanisms which are so well known that illustration thereof is unnecessary.

The engine illustrated in the accompanying drawings comprises a combustion chamber-l having cylindrical walls Q in which a piston 3 is reciprocablv mounted. The cylinder walls 2 are provided with a water jacket 4 which encloses the upper and major portion of the cylinder. Preferably thel cylinder is made with an integral head 5 which is so constructed that extensions G of the water jacket form a portion of the cylinder head. Preferably the cylinder head is provided with a central inlet aperture 7, the wall 8 surrounding which is of sutlicient thickness and mass to absorb and retain a relatively large amount of the heat produced by the explosion of the charge. The wall of the aperture 7 desirably is so constructed as to present a reentrant surface.

its illustrated herein the upper portion 9 of the wall of the aperture diver-ges from the entrance to the aperture, then merges into the curved central portion l0, while the lower portion 11 of the aperture converges, as illustrated more particularly in Fig. 3.

A valve casing 12 is secured to and preferably located entirely outside of the cylinder head and comprises an annular base 13 which is secured to the cylinder head by suitable bolts. The valve casing is provided with a transverse central intake i4 having an intake port 15 communicating with the inlet 7 in the cylinder head. The hydrocarbon mixture, is supplied to the intake 14e through the usual conduit 16 leading from the manifold 17 which is provided with `the usual throttle valve 1S. The valve casing is also provided with a preferably plurality of exhaust ports 19 and 20 having suitable exhaust valves and communicating respectively through conduitsv 2l and Q2 with an exhaust pipe 23 or manifold. The conduits 2l and 22 leading from the exhaust ports preferably enclose the wall of the intake i4.

The intake port 15 is, provided with a preferahll7 conical valve z* `at A the face ol' which formsa continuation of the upper inclined surface 9 of the Vall of the inlet i. The intake valve 25 is of conical form complementary to the wall 2.4 of the intake port and is provided with the usual stem 26 and head 27 which is operated by a cam or tappet Q8. A spring 29. fitting upon a boss 30 extending upwardly from the valve casing 12, engages at its upper end thehead 2T of the valve stem and normally acts to hold the valve seated in a usual manner.

In the-operation of the engine an explosive mixture,4 preferably over-rich in hydrocarbon, is supplied from a usual type of carburetor to the manifold and is drawn in to the combustion chamber upon thesuction stroke of the piston. As the explosive mixture is thus drawn in through the intake port 15 the conical valve Q5 diverts the incoming explosivt` mixture into the orm of a thin annular film along the Walls 24 of the valve casing and the diverging portion 9 of the wall ofthe inlet aperture, thus causing the globules of fuel to impinge upon the reentrant or curved surface 1() of the Wall of the inlet aperture. The globules thus impinging upon the wall of the aperture are broken up and deflected. By reason of the converging form of the lower portion 11 of the wall of the aperture the globules thus deflected are caused to converge so that such globules as are unbrokenby their Contact with the recntrant wall of the inlet aperture will he caused to impinge upon other unbroken globules and be broken up within the upper portion of the cylinder. This deflection of the film of the charge also causes a more complete mixing and distribution of the atomized and vaporized charge in the upper portion of the cylinder. As the wall of the inlet aperture, against which the globules of fuel impinge, is highly heated the. 'mixture which enters the cylinder is raised to a relatively high temperature so that stratification of the charge in the upper p ortion of thc cylinder is more effectively produced.

A further feature of the invention consists in combining with the mechanism for introducing the charge above described means for introducing air at substantially atmospheric pressure adjacent the end of the charging stroke. 'Ihis is accomplished by providing a relatively small port 31 in the cylinder wall adjacent the limit of the piston stroke and securing in said aperture a valve adapted to permit the automatic admission of air when the port 31 is opened by the piston passing below it. The valve casing as illustrated comprises a body portion 32 having a screw threaded apertured extension or stem engaging the walls of the port 31, said bodyportion being provided with a valve chamber 33. A cap 34 is screwed into the outer end of the chamber 33 and is provided with a central port 35 communicating with said chamber and with the atmosphere. A valve 436. is located within the chamber 33 and is provided with a stem 37 extending through the port 35. The outer end of the valve stem 37 is provided with a head 38 and a helical spring 39, abutting at one end against the head 38 and at the other end against the cap 34, normally tends to hold the valve 35 seated against the under or inner face of the cap 34.

When in the operation of the engine the piston head passes below the port 31 the partial vacuum within the cylinder will withdraw the valve 36 against the spring 39 and admit air at substantially atmospheric pressure to enter the lower portion of the c linder. By reason of this construction, t erefore, a suicient amount of cool air entersthe cylinder at the end of each induction stroke to produce substantially atmospheric pressure within the comibustion chamber irrespective of the amount of charge which is introduced, or the condition or quality of the charge'. The difference in temperature between the -air thus intro duced and the charge insures stratification of the contents of the cylinder. However, a suicient amount of the air thus introduced mixes with the charge to provide suicieut oxygen to produce a complete combustion of the charge even though rich in hydrocarbon. The greater portion of theair thus admitted, however, remains in the state of stratification and serves uponthe exhaust stroke of the piston to expel and thoroughly scavenge the cylinder of the products of combustion.

A further feature of the invention consists in providing novel means -for insuring the ignition of the charge. This is accomplished by providing a by-passin the heated walllof the cylinder head through which a portion of the over-rich mixture is diverted and igniting the mixture at or adjacent the point at which it enters the cylinder. In the preferred embodiment of the invention ilvlustratcd a by-pass 40 leads from the reentrant portion 9 of the wall of the inlet in the cylinder head in parallelism with the inner wall of the cylinder head and terminates in a port 41 leading into the cylinder at any desirable point, preferably adjacent the cylindrical wall of the cylinder. The ignition of the over-rich mixture is accomplished by a spark plug 42 seated in the cylinder wall and preferably extending into the by-pass immediately above the port which leads into the cylinder.v

It will be understood that the embodiments of the invention disclosed herein are illustrative and not restrictive, and that various modifications in form, construction and arrangement of parts may be made within the spirit and scope of the following claims. i

Having thus described my invention, what. l claim as new,` and desire to secure by Letters Patent, is:

l. An internal combustion engine comprising a metallic cylinder having a head of sutlicient mass to absorb a large amount ot' heat presenting a fiat inner face and providedwith a substantially flat inner face and with a sul'istantially central fuel inlet port having a reversely conoidal re-entrant wall, means for supplying a regulated mixture of air carbureted with liquid and hydrocarbon to said port, an inlet valve in said port having a peripheral surface compley mentary to one of the 'surfaces of said annular re-entrant port wall operable to admit said mixture into the cylinder during the outward stroke of the piston and to direct a thin tilm ot' said mixture against the highly heated wall of said port and co-operating with said wall to direct said film in a converging conoidal form into the cylinder adjacent the head thereof and thereby to cause unbroken globules of the hydrocarbon to impinge upon one another and also to cause the charge to be thoroughly mixed and distributed in the portion of the cylinder adjacent its head and a spring actuated poppet valve automatically operable to admit a supplemental 4amount of air'into said cylinder adjacent. the end 'of the piston near the end ot` each outward stroke thereof and to prevent the escape ot' any of the supplemental air thus introduced. whereby an approximately constant volumetric charge will be intro-` duced into the cylinder irrespective of the amount or quality of the charge of explo'- sive mixture and an effective stratification of the air and explosivo mixture will be pro duced.

2. An internal combustion engine comprising a metallic cylinder having a head of suhcient mass to absorb a large amount of heat and provided with a substantially flat inner face and a central fuel inlet port having a re-entrant Wall and with a pair of eX- haust ports located adjacent the Wall of the cylinder, a valve asing secured to said cylinder head having an inlet conduit, for supplying a mixture ot air and carbureted liquid lrvdrocarbon7 communicating with said inlet port, an exhaust conduit in said valve casing having branches communicat ing with the exhaust ports of said cylinder and extending in parallelism with said inlet port with a thin wall therebetween, a Valve mounted in said valve casing having an inclined periphery complementary to one of the rc-entrant walls of said port operable to direct a thin lilm of said mixture against the highly heated re-entrant Wall of said port and cri-operating with Said re-entrant Wall to direct said film in a converging conoidal form into the upper portion ot' said cylinder and thereby to cause unbroken globules of the hydrocarlmn to impinge upon one an other and also to cause the charge to be thor oughly mixed and distributed in the portion ot the cylinder adjacent. the head thereof and means automatically operable to admit a supplei'nental amount of air into said cylinder adjacent the end of the piston near the end of the charging stroke suilicient in quantity to produce a substantially constant volumetric charge in said cylinder irrespective of the amount or quality of the charge of explosive mixture introduced and to prevent the escape of any of the supplemental air thus introduced, whereby an approximately constant volurnetric charge will be introduced into the cylinder irrespective ot the amount or quality of the charge of explosive mixture and an etl'ective stratiiication of the air and explosive mixture will be produced.

3. An internal combustion engine comprising a cylinder having a head provided with an inlet port having a reversely conoidal re-entrant wall, a piston reciprocable in said cylinder, means for introducing an explosive charge of hydro-carbon and air into said Cylinder through said inlet port during the charging stroke ot the piston, means for admitting air at substantially atmospheric pressure into said cylinder adjacent the end of the charging stroke of the piston sutlicient in quantity to produce an approxi-A mately constant. charge irrespective of the amount or quality of the mixture introduced, a by-pass in said cylinder head leading from said re-entrant angle ot said inlet port to said combustion vchamber and a spark plugin said by-pass operable to ignite the fuel passing through said by-pass whereby ignition ot' the charge in the cylinder is insured irrespective of the leanness of the explosive mixture in the cylinder caused by the introduction ot' the air adjacent the end of the intake stroke.

ln testimony whereof, I have signed my name to this specification.

WILLIAM L. DEMPSEY. 

